Process for the manufacture of metallic diaphragms of electrolytic cells



UNITED STATES PATENT OFFICE."

RODOLPHE IBEGHKRANZ, OF'CAROUGE-GENEVA, SWITZERLAND.

rnocnss ron THE murecruar: or mi'rntmc niummems or amc'rnomrrrc- CELLS.

1,388,754, Specification of Letters Patent. Patented ,Allg, 23, 1921. N0 Drawing. Application filed June 1, 1926. Serial No. 885,715.

Toall whom it may concern:

Be it known that I, RonoLrHE PECHKRANZ,

engineer, a citizen of Switzerland, residingat Carouge-Geneva, Canton of Geneva, in the Confederation of Switzerland, have invented certain new and usful improvements in- Process es for the Manufacture of Metallic Diaphragmsof Electrolytic Cells, of which the following is a specification. 10 The resent invention relates to, the manufacturrgpf metallic bodies and in particular of meta diaphragms for electrolytic cells; and it contemplates the production of a thin, porous diaphragm constructed of a metal nickel, for instance,or some other metal of the same group-which 'isinert in respect of 'thechemical reactions of the particular electrolyte to be used in the cell.

In carrying out the invention, a suitable foundation or sup ort is first treated to form a. matrix for the iaphra the surface of the matrix being provide at a multitude oft ointswith fine particles of electrical insuating material, after which such surface is 2 oxidized. The support so treated is then placed in an electrolytic bath through which a current is caused to pass, so as to eifect the deposit, galvanoplastically, of a coat of nickel upon the prepared surface of the matrix; and at the conclusion of the operation the coating or layer is stri ped from the matrix, gwhich can readily 'be one owing to the interposed oxidized layer between the coating and the matrix which pregentsthe coating and matrix from adhering together. The detached la er will be found to be covered all over wit extremely fine holes'which are produced by the articles of insulating 'material durin the ormation of the coati'ng, such partic es precluding the deposit of the nickel thereon as will be understood; The orosity of the. diaphragm can be regulated y varying the character and siza of the insulating particles, and the iffatrlx itself can'be used repeatedly until worn out.

methods may be adopted. For example, the surface 'of a copper or other plate maybe covered with mm te' cells by treatlng 1t according to the w ll-known photo-engraving process; and these cells are then filled wlth suitable insulating enamel by daubmg the enamel all over the plate surface, afterwhich lthecsaid surface .ispumiced, so as toleave bare the metal network between the cells,

In "preparing the matrix, a number of The small particles of enamel are retained in their respective cells by means of a coatmg of mckel which is then deposited electrolytically upon the plate and which, as it increases in thickness, partially closes the cells and thus. forms a virtual setting for each individual particle This completes the -matrix, the surface of which is thereupon oxidized in some suitable way; and then the coating of nickel, or other metal of the same group, formin the diaphragm-is deposited electrolytica 1y upon the oxidized surface, such nickel coating being quite thin (for instance, a-fe-w hundredths of a millimeter; and consequently offering only a sli ht resistance to the passage of the electro ytic current. i Instead of proceeding as above described, it is possible to construct the matrix by first 3 oxidizing the plate and then spraying uniformly over its oxidized surface a suitable insulating varnishin pulverized condition, the particles of varnish forming the holes in the nickel coating thereafter de osited upon the plate. f Or the minute insu ating points so might be produced upon the oxidized surface of the plate by impression; and still other methods of procedure might be adopted.

' l The invention might also be carried out by treating a textile fabric.for example, '5 cotton, muslin, thread or'silk, etc.-in such a way as to Tconvert it from a non-conductor to a conductor of current, and then depositing upon it the coating of nickel 'or other metal.

I claim as my invention: I

1. Aprocess of manufacturing metal diaphragms for electrolytic cells, comprising the steps of, depositing electrolytically upon a foundation a coating of a metal which will be inert to the chemical reactions of the elebtrolyte in the cell in which it is'to be used; and then detachingthe metal coating from the foundation. p

2. A process accordin to claim 1, in which the metal deposits upon the foundation is one of the nickel group. i

3. A process of manufacturing metal diaphragms for electrolytic. cells, comprising the steps of-depositinga coatin of nickel electrolytically upon a suitable oundation; and then detaching the nickel coatingifrom the foundation,

4. A process of manufacturing metal diaphragms for electrolytic ,cells, comprising the steps of providing upon the surface of a suitable metal platea multitude of small particles of insulating material"; oxidizing said surface; depositing electrolytically upon such oxidized surface a'coating of a metal which will be inert to the chemical reactions of the electrolyte in the cell in which it is to be used; and then detaching the metal coating from said plate. v

6. A process of manufacturing metal diathe steps of forming a matrix which is provided upon its surface at a -multitude of points with fine particles of insulating material; oxidizing the surface of the matrix;

depositing electrolytically upon such oxidized surface a coating of a metal which will-be inert to the chemical reactions of the electrolyte in the cell in which it is to be used; and detaching the coating from the matrix. 80 I 7. A process of manufacturing metal' ,di aphragms .for electrolytic cells, comprising the steps of forming a matrix which is provided upon its surface at a multitude of points with fine particles of insulating ma-'35 terial; forming upon the surface of the ma- ,trix a"'layer of relatively-low electrical re- -sistance; depositing electrolytically upon such layer a coating .of a metal which will be inert to the chemicalreactions of theelec- 40 trolyte in the cellin which it is to be used; and detaching the coati'n from the matrix.

8. A thin porous diap ragm for electrolytic cells constructed of a metal -which is inert to the chemical reactions of theelectroo lyte in the cellr. phragms for electrolytic cells, comprising i 9. A thin, porous, nickel diaphragm for electrolytic cells. 0

In testimony whereof I afiix my fsignature in presence of two witnesses. I

RODOLPHE PEOITLKRANZ.

Witnesses:

D. Ron. DE Wohs'rLINBERG',

'EDW. EMMANNESl 

